The injury first cropped up the first week of training camp, and it now has Avril a question mark when the regular season begins in Carolina.

Wide receiver Sidney Rice sat out Monday's practice as a precautionary measure, and he will also be held out of the Seahawks' final preseason game Thursday against the Raiders. (AP)

"We don't know if he's going to be ready," coach Pete Carroll said of Avril. "We don't know that right now."

Avril is part of an increasingly cloudy forecast. Defensive end Chris Clemons won't be practicing this week, and while he hasn't been ruled out to begin the season as he continues to rehabilitate from offseason knee surgery, there's been no speculation that he will be ready by the coach, either.

Then there's receiver Sidney Rice, who sat out practice Monday in what Carroll described as a precautionary move. Rice won't play in Thursday's preseason finale as Seattle is planning to have him ready to start the regular season.

"We're taking care of him," Carroll said of Rice. "We're pointing to the opener for that."

As for the defense, that remains a question. Seattle has yet to sack an opponent's starting quarterback in a preseason game this year, something that has to do with the fact that Avril and Clemons have yet to play. But as of right now, there's no guarantee Seattle gets either one back.

Knee-d to know

Defensive tackle Jesse Williams' rookie year is over before it began, as the fifth-round pick out of Alabama was placed on injured reserve Monday, thereby ending his season.

"His knee just wasn't responding well enough," Carroll said. "It's going to take a long time to give him the consideration to get him right. This is the right thing we can do for Jesse. He did everything we asked of him and looked good when he had his chances, but his knee wasn't holding up so we've just got to give him a big break."

Williams was a starter on Alabama's national championship team and one of the strongest players available in this year's draft. There were concerns about his knee, though, which is a reason he fell to the latter half of the draft. He did not practice last week and was unable to play in the preseason game at Green Bay.

Williams was a rarity in that Seattle traded up to select him in the fifth round, and his loss shouldn't be minimized.

"He's such a big and square guy that he is able to hold things at the point of attack," said Dan Quinn, Seattle's defensive coordinator. "You know us at the run game, if we could get bigger we would. So you just miss a guy with the style and presence he could bring."

Williams wasn't the only rookie unable to practice Monday. Third-round pick Jordan Hill remains sidelined by a strained biceps, which creates a clear path to the starting job for Tony McDaniel, the eighth-year pro who made his Seahawks debut on Friday after missing the first two preseason games with a groin injury.

"It was good to see him in there," Quinn said of McDaniel. "We've kind of seen it out here in practice so we were so anxious to get a chance to him."

Is McDaniel the likely starter next to nose guard Brandon Mebane at this point?

"We'll wait and see," Carroll said. "I don't know that yet. Tony had a nice game. He did well. He's active and was aggressive, knocked a ball down, got some movement in his pass rush. We were happy with the way he played so we'll need to put another week together."

Notes

• LG James Carpenter returned to practice after missing the past few weeks with a sore foot.

• DT Brandon Mebane suffered what appeared to be a groin injury during practice, and Carroll said the team will have to wait to know if it's a significant injury.

• CB Antoine Winfield did not play in last week's preseason game because of a sore knee, but he was back practicing Monday.